Gel coat removal - water sanding vs. straight line sanding

On Feb 6, 7:57*pm, bildan wrote:
On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171....

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

On Feb 7, 6:26*am, wrote:
On Feb 6, 7:57*pm, bildan wrote:





On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH- Hide quoted text -

- Show quoted text -

Right on Uncle Hank, I use the Porter-Cable orbital sander with DA and
variable speed turning a soft pad with 6" sticky back sandpaper, 60
grit gets through the hard outer surface better (quicker) than 80
grit. I use the 18" air board, but it pulls my 11 cu/ft/min compressor
down in about 5 minutes.
I wouldn't worry too much about the dust, an MD told me the particles
from fiberglass and gelcoat are quite large and not the size that gets
trapped in your lungs. Use a good quality dust mask with inhalation/
exholation valve.
Grrrrrrrrrrrrrrrrrrrrrrrr, glad I'm not doing any of that any more!
JJ

On Feb 7, 7:26*am, wrote:
On Feb 6, 7:57*pm, bildan wrote:



On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.

On Feb 7, 10:54*am, bildan wrote:
On Feb 7, 7:26*am, wrote:





On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

On Feb 8, 12:05*pm, wrote:
On Feb 7, 10:54*am, bildan wrote:



On Feb 7, 7:26*am, wrote:

On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control..
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

Yep, I'm sure it takes a lot of experience.

Another thought struck me. Are you familiar with "rivet shavers" that
cut countersunk rivets flush with an aluminum skin?

They have a sharp rotary cutter inside a micrometer adjustable housing
that lets the user adjust the depth of the cut to produce a perfectly
smooth rivet 'shave'. Maybe something like that....

I expect the idea would be to quickly and accurately remove all but a
few thousandths of gelcoat which would then be removed with the 5"
orbital sander.

On Feb 8, 12:34*pm, bildan wrote:
On Feb 8, 12:05*pm, wrote:





On Feb 7, 10:54*am, bildan wrote:

On Feb 7, 7:26*am, wrote:

On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work..
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

Yep, I'm sure it takes a lot of experience.

Another thought struck me. *Are you familiar with "rivet shavers" that
cut countersunk rivets flush with an aluminum skin?

They have a sharp rotary cutter inside a micrometer adjustable housing
that lets the user adjust the depth of the cut to produce a perfectly
smooth rivet 'shave'. *Maybe something like that....

I expect the idea would be to quickly and accurately remove all but a
few thousandths of gelcoat which would then be removed with the 5"
orbital sander.

I think this is what you are talking about Bill:

http://www.gelplane.co.uk/gelplane/product.asp

I have thought about both the plane as well as testing bead/sand
blasting. Never got around to having the time to test both. Used the
7" rotary sanding technique like everyone else.

The old Sailplane Racing Association web pages were great information
on refinishing. Not sure if that information was moved to a new site.

On Feb 8, 1:40*pm, Tim Taylor wrote:
On Feb 8, 12:34*pm, bildan wrote:





On Feb 8, 12:05*pm, wrote:

On Feb 7, 10:54*am, bildan wrote:

On Feb 7, 7:26*am, wrote:

On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal..
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

Yep, I'm sure it takes a lot of experience.

Another thought struck me. *Are you familiar with "rivet shavers" that
cut countersunk rivets flush with an aluminum skin?

They have a sharp rotary cutter inside a micrometer adjustable housing
that lets the user adjust the depth of the cut to produce a perfectly
smooth rivet 'shave'. *Maybe something like that....

I expect the idea would be to quickly and accurately remove all but a
few thousandths of gelcoat which would then be removed with the 5"
orbital sander.

I think this is what you are talking about Bill:

http://www.gelplane.co.uk/gelplane/product.asp

I have thought about both the plane as well as testing bead/sand
blasting. *Never got around to having the time to test both. *Used the
7" rotary sanding technique like everyone else.

The old Sailplane Racing Association web pages were great information
on refinishing. Not sure if that information was moved to a new site.


I want one of these for gliders!

A gelcoat removing robot.

http://www.moverbo.nl/startpeeler.html

On Feb 8, 12:40*pm, Tim Taylor wrote:
On Feb 8, 12:34*pm, bildan wrote:





On Feb 8, 12:05*pm, wrote:

On Feb 7, 10:54*am, bildan wrote:

On Feb 7, 7:26*am, wrote:

On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal..
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

Yep, I'm sure it takes a lot of experience.

Another thought struck me. *Are you familiar with "rivet shavers" that
cut countersunk rivets flush with an aluminum skin?

They have a sharp rotary cutter inside a micrometer adjustable housing
that lets the user adjust the depth of the cut to produce a perfectly
smooth rivet 'shave'. *Maybe something like that....

I expect the idea would be to quickly and accurately remove all but a
few thousandths of gelcoat which would then be removed with the 5"
orbital sander.

I think this is what you are talking about Bill:

http://www.gelplane.co.uk/gelplane/product.asp

I have thought about both the plane as well as testing bead/sand
blasting. *Never got around to having the time to test both. *Used the
7" rotary sanding technique like everyone else.

The old Sailplane Racing Association web pages were great information
on refinishing. Not sure if that information was moved to a new site.- Hide quoted text -

- Show quoted text -

The Gel-plane looks interesting, but the photo shows gelcoat being
removed from a boat that has mat structure (chopped fibers & resin)
and it doesn't matter much if you cut the top off the fibers. In a
sailplane the structure is cloth and it matters a whole bunch if you
even nick a few fibers. The real problem is the depth of the gelcoat
isn't uniform. Remember how it is built, gelcoat is sprayed into a
prepared mold and experience has shown that extra gelcoat is needed at
all edges and openings, spoilers, etc. Now start grinding it off and
you soon see that you must stop here, but keep going deeper over
there. I have tried sand-blasting (went right through in a heartbeat)
and paint remover ( just turned everything brown). Alas, I have found
nothing to beat good the old orbital sander. One can train high school
kids to do it, but they soon move on to more interesting work. We are
taliking about a mind-knumbing boring, filthy dirty, noisy, nasty,
activity that nobody is his right mind would do for a few worthless
dollars. Speaking of the worthless dollar, this is a good time to buy
a sailplane.................its got to be worth more worthless dollars
in the future because our national debt will keep eroding the value of
our already worthless dollar. Does everybody realize that every US
taxpayer owes $140,000.00 as his/her part of out national debt? OK,
enough of that..................Go out and buy a sailplane today, it
will never cost less than it does today.

JJ Who can make you a good deal on a fine little 2-place ship that
was owned by a little old lady who only flew it on Sundays, but she
accidently flew it into a tree..........not to worry, it has been
expertly repaired and refinished by a master abrasives technician.

On Feb 6, 12:54*pm, LS3 Pilot wrote:
What's the best tools to safely and effectively removing the old gel?

Checkbook ! :-)

On Feb 8, 2:51*pm, JJ Sinclair wrote:
On Feb 8, 12:40*pm, Tim Taylor wrote:



On Feb 8, 12:34*pm, bildan wrote:

On Feb 8, 12:05*pm, wrote:

On Feb 7, 10:54*am, bildan wrote:

On Feb 7, 7:26*am, wrote:

On Feb 6, 7:57*pm, bildan wrote:

On Feb 6, 10:54*am, LS3 Pilot wrote:

Trying to do some work on my ship. *Does anyone that reads this forum
have experience in the best way to remove gelcoat? *I've got an area
thats too big to hand sand on the wing that needs some work.. *A friend
suggested I buy a water sander that continuously feeds water to the
sander (similar to a pneumatic powered straight line sander).

What's the best tools to safely and effectively removing the old gel?

There's a thing called an "air file" auto body shops use.

http://www.pivco.net/index.php?main_...roducts_id=171...

It's a linear oscillating compressed air driven sander about 18" long
and 2.25" inches wide. *I've been told they work pretty well with 80
grit and they have less chance of digging into the fiberglass than a
rotary grinder. *Since it's air driven, I suppose you could safely use
wet sanding and avoid the dust.

I have used the following in order to find the "best"(for us) tools
fo gelcoat removal.
3 inch air rotary disc sander.- Too small- blows dust all over- noisy
7 inch electric disc sander. Too harsh for us and not easy to control.
Quick but likely to do damage easily.
18 inch air powered linear sander. Noisy. Not good except single
contour. Blows dust around. Need big compressor.
4 inch belt sander. Fast. tricky to use.
4 inch grinder with disc sanding attachment. Fast, fairly easy to
control. inexpensive. Slings dust everywhere.
5 inch electric orbital sander. Very uniform controllable removal.
Lowest dust generation in room. Easiest to use by unskilled or
learning helpers.
Only ones we use now are last 2 with last one doing 90% of the work.
Feel free to relearn the lessons already learned- we all seem tempted
to find the better way that nobody has found. Understand from the get-
go, there is no easy way to do this job.
Have "fun".
UH

It's still early and I'm working on my first cup of coffee but...

Might it be possible to make a support block that would limit the
"exposure" of the cutting surface on more aggressive sanders so as to
prevent it digging in? *It would work sort of like a block plane.
The idea is to use a fast cutting tool but limited to a very shallow
cut.- Hide quoted text -

- Show quoted text -

Might work if the surface we are sanding is straight and uniform over
significant distance.
And the surface we are sanding to is straight and uniform.
And the abrasive medium doesn't wear.
None of these occurs on the projects I work on.
Finding the "easy" way that all the folks that have done this before
is seriously tempting. By the time you develop and test the tool, you
can learn how to use the proven tools pretty effectively.
Well known shop scenario- voice is the worker:
This whizbang (grinder, sander insert tool here) really does much
better than the hard way I keep reading about.
Goin' pretty good- this isn't so tough.
One more pass and it'll be just right.
Damn!
RAS- How do I fix a hole in my(substitute part) skin?
Another thread!
Been there- done that.
You can't buy experience, but you DO pay for it.
FWIW
UH

Yep, I'm sure it takes a lot of experience.

Another thought struck me. *Are you familiar with "rivet shavers" that
cut countersunk rivets flush with an aluminum skin?

They have a sharp rotary cutter inside a micrometer adjustable housing
that lets the user adjust the depth of the cut to produce a perfectly
smooth rivet 'shave'. *Maybe something like that....

I expect the idea would be to quickly and accurately remove all but a
few thousandths of gelcoat which would then be removed with the 5"
orbital sander.

I think this is what you are talking about Bill:

http://www.gelplane.co.uk/gelplane/product.asp

I have thought about both the plane as well as testing bead/sand
blasting. *Never got around to having the time to test both. *Used the
7" rotary sanding technique like everyone else.

The old Sailplane Racing Association web pages were great information
on refinishing. Not sure if that information was moved to a new site.- Hide quoted text -

- Show quoted text -

The Gel-plane looks interesting, but the photo shows gelcoat being
removed from a boat that has mat structure (chopped fibers & resin)
and it doesn't matter much if you cut the top off the fibers. In a
sailplane the structure is cloth and it matters a whole bunch if you
even nick a few fibers. The real problem is the depth of the gelcoat
isn't uniform. Remember how it is built, gelcoat is sprayed into a
prepared mold and experience has shown that extra gelcoat is needed at
all edges and openings, spoilers, etc. Now start grinding it off and
you soon see that you must stop here, but keep going deeper over
there. I have tried sand-blasting (went right through in a heartbeat)
and paint remover ( just turned everything brown). Alas, I have found
nothing to beat good the old orbital sander. One can train high school
kids to do it, but they soon move on to more interesting work. We are
taliking about a mind-knumbing boring, filthy dirty, noisy, nasty,
activity that nobody is his right mind would do for a few worthless
dollars. Speaking of the worthless dollar, this is a good time to buy
a sailplane.................its got to be worth more worthless dollars
in the future because our national debt will keep eroding the value of
our already worthless dollar. Does everybody realize that every US
taxpayer owes $140,000.00 as his/her part of out national debt? *OK,
enough of that..................Go out and buy a sailplane today, it
will never cost less than it does today.

JJ * *Who can make you a good deal on a fine little 2-place ship that
was owned by a little old lady who only flew it on Sundays, but she
accidently flew it into a tree..........not to worry, it has been
expertly repaired and refinished by a master abrasives technician.

The thing is, there's a bunch of nice airworthy old gliders out there
with bad gelcoat. Right now, replacing gelcoat costs more than
they're worth. If an economical way could be found to redo the
gelcoat, that would be a good thing, wouldn't it?